Drug interactions
Erythromycin + Nelfinavir
Severity: Moderate
Erythromycin and Nelfinavir: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Both drugs are CYP3A4 substrates and inhibitors, so each can raise the other's levels. Increased erythromycin exposure adds to QT and gastrointestinal risks.
What this interaction means in plain words
Erythromycin and Nelfinavir can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Erythromycin belongs to Anti Bacterial; Nelfinavir belongs to Anti Virals.
Why it happens
Mutual inhibition of CYP3A4-mediated metabolism.
What to do
Monitor for erythromycin toxicity and nelfinavir adverse effects, and consider an ECG in patients with QT risk. Use an alternative antibiotic if feasible.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Erythromycin
- Conivaptan + Erythromycin Contraindicated
- Dihydroergotamine intranasal + Erythromycin Contraindicated
- Dihydroergotamine + Erythromycin Contraindicated
- Domperidone + Erythromycin Contraindicated
- Dronedarone + Erythromycin Contraindicated
- Droperidol + Erythromycin Contraindicated
Other interactions of Nelfinavir
- Alfuzosin + Nelfinavir Contraindicated
- Avanafil + Nelfinavir Contraindicated
- Dronedarone + Nelfinavir Contraindicated
- Eletriptan + Nelfinavir Contraindicated
- Ergotamine + Nelfinavir Contraindicated
- Flibanserin + Nelfinavir Contraindicated
Frequently asked questions
Can I take Erythromycin with Nelfinavir?
MediHelp rates the interaction as moderate. Erythromycin and Nelfinavir can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Both drugs are CYP3A4 substrates and inhibitors, so each can raise the other's levels. Increased erythromycin exposure adds to QT and gastrointestinal risks.
How serious is the interaction between Erythromycin and Nelfinavir?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for erythromycin toxicity and nelfinavir adverse effects, and consider an ECG in patients with QT risk. Use an alternative antibiotic if feasible.
What other medicines interact with Erythromycin?
MediHelp also lists interactions of Erythromycin with, for example, Conivaptan, Dihydroergotamine intranasal, Dihydroergotamine. The full list is on the Erythromycin page.
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